It is well known that DBS of the posteroventral part of the medial pallidum (GPi) eliminates rigido-hypokinesia and dyskinesia but often shows a recurrence of gait freezing and wearing-off in Parkinson's disease. In the course of DBS surgery, we found a unilateral high-frequency stimulation of the middle-dorsal part of the GPi in the non-dominant hemisphere improved gait freezing postoperatively much longer than destructive surgery. DBS of the subthalamic nucleus alleviated hypokinesia and wearing-off, and could reduce levodopa dose as a result drug-induced dyskinesia decreased in some cases. Unilateral DBS of the STN usually showed a recurrence of the symptoms around three months after surgery and bilateral DBS needed to obtain good results in long postoperative days.Microrecording disclosed an excessive high backgroud activitiy in the STN as well as the GPi, offering a useful study to delineate the surgical targets. Intraoperative injection of levodopa (1mg/kg, i.v.) decreased the background activity in the GPi 30-40% of the pre-injection state, however, did not change those of the GPe and STN.This suggests that the D2-mediated indirect pathway in the lenticular nucleus is hard to be modified by dopamine and so clinical importance of DBS of the STN which composes the indirect pathway.Neuroimaging studies using SPECT revealed that a selective increase of CBF in the pre-SMA in bilateral hemispheres was induced by stimulation of the middle-dorsal GPi on the right side, and a CBF increase in the broad area of both hemispheres including the high convexity of the frontal lobe, anterior half of the medial cortex, thalamus and lenticular nucleus was produced by STN stimulation on the right.